A switching device of the type described above is described in German Patent No. 44 20 580. Access of a tool to the traversing mechanism here can be blocked by a protective device which can be operated as a function of the position of the blocking bar, where one of the working faces of the blocking bar can be covered by an opposing face of the indicator element which depends on the position of the operating shaft. This arrangement requires two-handed operation on the part of the user. First, the OFF key must be depressed before the protective device assigned to the traversing mechanism is opened or the closing device can be operated.